Sleep & Heart Health

Sleep Soundly for Heart Health

By Steven Georgeson, MD

If you're not getting a restful night's sleep, you may be causing damage
to your heart. Undiagnosed sleep disorders can cause or worsen many cardiac
conditions. Half of all patients with high blood pressure, atrial fibrillation
and congestive heart failure and one third of patients with coronary artery
disease suffer from obstructive sleep apnea, the most common sleep-related
breathing disorder.

How does your sleeping pattern affect your heart? In general, sleep relaxes
the cardiovascular system. Obstructive sleep apnea prevents that relaxation.
It occurs when the upper airway is either partially or completely closed
during sleep. This closure causes periods of stopped breathing which lowers
the oxygen level of the blood and increases blood pressure and adrenaline levels.

By fragmenting sleep and by producing surges of adrenaline, individuals
with obstructive sleep apnea are kept in a continually activated state.
This activation prevents the normal decrease in nighttime blood pressure,
increases the irritability of the heart's electrical system, causes ongoing
inflammation and alters the pumping function of the heart.

People who are overweight and suffer from obstructive sleep apnea are at
high risk for developing atrial fibrillation, the most common type of
irregular heart rhythm. In addition, people with untreated obstructive
sleep apnea have an increased risk for a second episode of atrial fibrillation
after the heart is shocked to restore the normal heart rhythm.

Sleep disorders may also cause or worsen congestive heart failure by a
variety of mechanisms. Obstructive sleep apnea will increase the pressure
and stress in the heart, making it harder to pump blood to the body. By
restricting oxygen intake, it also impairs the heart's pumping ability.

The majority of patients with obstructive sleep apnea remain undiagnosed.
Many either have no symptoms or do not recognize the symptoms related
to their sleep disorder until they are treated for heart disease. Symptoms
include snoring, daytime sleepiness and recurrent episodes of waking suddenly
or gasping upon waking. While many people associate sleep apnea with obese
middle-aged men, one third of people with the disorder are women and many
are not obese.

Obstructive sleep apnea may be an underlying cause of heart disease in
people who are obese with difficult-to-control blood pressure, congestive
heart failure or multiple episodes of atrial fibrillation and in individuals
with high blood pressure who cannot control it with multiple medications.

If you suspect that you may have a sleep disorder, talk to your doctor.
A sleep study may be recommended to determine the cause of your sleep
disturbance. A sleep study requires an overnight stay at a sleep lab for
monitoring of the blood oxygen level, the heart rate, the stage of sleep,
jaw muscle tone, sleep position and chest and stomach wall movements.

If you are diagnosed with a sleep disorder, a variety of treatments are
available to improve your heart condition and quality of life, including
weight loss, oral appliances, medications, surgery and the use of a continuous
positive airway pressure (CPAP) machine, which helps keep the airway open
during sleep by applying air pressure through a mask. The CPAP machine
helps eliminates apneas, keeps sleep from being fragmented and corrects
the adverse effects on the body seen in people with obstructive sleep
apnea. It can also improve vitality, physical functioning, social functioning
and general health perception. This treatment improves the mechanics of
the heart, reduces symptoms in patients with heart failure, increases
the pumping function of the heart and lowers both nighttime and daytime
blood pressure. As a result, the number of blood pressure medications
or the dosage of medication can often be reduced.

Dr. Georgeson is chief of cardiology services at Robert Wood Johnson University
Hospital Somerset.